Several GOP candidates had already lined up to challenge the 15-term lawmaker in the primary before his retirement announcement last week. Former U.S. Attorney Susan Brooks, former Rep. David McIntosh, former Marion County Coroner John McGoff and attorney Jack Lugar will now square off in the open-seat primary.

Previously, Roll Call had rated the race as Likely Republican. But in light of Burton’s retirement, we are changing the rating to Safe Republican. The winner of the GOP primary will most likely serve as the next Member of Congress from this district.